CFL and LED lamps: White light in a 'green' world

Despite the attention focused on alternative energies to increase available power, measures intended to conserve energy represent an equally important story. Along with "making more," the energy challenge is also to "use less."

Hybrid vehicles have received justifiable attention in the car industry's conservation effort and certainly automobiles are a big part of the energy puzzle. Home and commercial lighting also represent significant consumption, accounting for 15 percent to 35 percent of all energy use (depending on whose numbers you believe). The workhorse incandescent lamp, evolved over so many years, remains in widespread use to be sure, but abysmal efficiencies--typically well below 5 percent--have spurred change.

Enter two technologies already helping and likely to grow as pressure mounts to reduce electricity consumption--the Compact Fluorescent Lamp (CFL) and LED lamp. Both are moving toward, if not being legislated into, more widespread application in the search for conservation.

The former of these two has been on a steady march toward affordability, and Planet Analog editor Bill Schweber recently sent me a pile of CFLs, now available as sub-$5 replacements for incandescent bulbs, as a not-so-subtle recommendation for a teardown.

But CFL is not alone, and Bill's hardware handout got me thinking more about the other contender in the game. LED lighting has made measured but steady progress as a viable replacement for the inefficient incandescent, and a high-brightness LED "downlight" recently brought to market caught my eye. We'll look at examples of both here.

LED's have to be kept cool to maintain their efficiency, that is why the heatsink is so large. Where as 100degC may seem ok for a power semi, LED's should be operated at <50.
I often wonder if the carbon cost of manufacture is taken into the equation when stating CFL's and LED's are greener.
Lastly someone has developed a nano scale treatment that makes incandescents >20% efficient. Maybe there will be a comeback ??

I have no experience with LED lighting, but over the last 10 years, I have slowly replaced most of my incandescents with compact fluorescents. Way back then, the colors were so bad that we only put them where the color didn't matter: the front hall, the garage, etc. Otherwise, my wife would complain that our skin looked yellow, or the carpet looked "sick" (under the CFLs of the time, it did!).
But this year we've replaced most of the incandescents in the family room, hall, laundry room, kitchen and other high-use areas with with CFL, with no complaints. All the reading lights are CFL (get the higher wattage bulbs to have enough light). The prices are low, and you can choose the light color (temperature) you want. The prices are very low at Home Depot and elsewhere.
I'm to the point where I buy a 4-pack of CFLs to get two that I need, then I go around the house hunting for other incandescents to replace. As of last weekend, all the fixtures I opened already had CFL. This is a testament to the CFL's color quality-I was unaware that they weren't incandescent.

What you are looking for is a high CRI (color rendering index). Most CFLs are abysmal at around 80 -- this a shade better than the original F40 cool-white bulbs.
But, you can do better; there are some good CFLs out there, at a cost ($15 or so each; look at the photography magazines or google for High CRI CFL).
You can get tube fluourescents with high CRIs as well (Phillips TL950 98 CRI) -- and it makes an incredible difference. I just wish HD and Lowes would quit with "sun-like" and "cool white" and post CRI numbers.
I haven't seen a CRI on LEDs yet, so I'm assuming they're embarassed about it.
Exception: GELcore LED's are UV and use the same rare-eath phospors as tubes do, so they have a line of High CRI LEDs.
-Thor Johnson
http://www.scientificconservation.com

Heatsink may be required for LED lamp because of the relatively small surface area of the light source, and its integration into the base. Original article seems to assume that most inefficiency arises from the power supply, which is not true. The heatsink helps to disipate heat conducted from the LEDs. The CFL source has a large area, poor conductivity, and is largely remote from the base housing.
In addition, LEDs may fall in efficiency, or fail, if overheated. Original article appears to assume that both types of fitting should be cooled to a similar temperature, but this may not be the case.

I switched over most of my household lamp fixtures to CFL about a years ago. The only fixtures I cannot change over are the two that are controlled by dimmers - you can't yet do that with a CFL. I've even got CFLs in two of my ceiling fan fixtures (the ones that don't have a dimmer control) and one yellow "bug light" CFL outside on my front porch.
While it's true that CFLs take time to warm up to full brightness, I haven't noticed that it is a problem that negatively affects our lifestyle. They are certainly bright enough initially to provide useful light, and they are at full brightness after just a few seconds.
The color temperature is also quite good. I have not noticed any of the "harshness" or "coldness" that some people claim to see with CFLs. The lamps I've been buying seem quite warm to me. The cost has come down significantly, so I can buy a four-pack for about 9 bucks, and I haven't had to replace any of my CFLs in the year or so that they've been in service. So far so good.
My main concern with CFLs is environmental. While I know that they must be recycled - and I've seen recycling bins at Home Depot - I'm not entirely convinced that the general public understands that they cannot be put in the trash. With standard tube florescents, it's difficult to just throw them away due to their size, but CFLs are so small, people may just naturally toss them in the garbage.